In the technical community that created and named the Internet, the convention is to capitalize when one is writing about the specific “internet” that we call the Internet and not to capitalize when referring to generic internets. In this case, the technical community is essentially acting as their own lexicographers and using the capitalization to add disambiguating information to the text. Think of it as a case of case-sensitive encoding.

Those who doubt the value of this distinction need only scan any of the thousands of documents on the site of the Internet Engineering Task Force. The IETF is responsible for the internet standards that make the Internet work. They should know how to spell the name of what they build.

If you “never capitalize internet and web,” you are simply indicating that you don’t understand the technical distinction between the Internet and an internet. Also, you don’t understand the difference between the Web and a web. (For instance, Tim Berners-Lee clearly wrote the first Web browser. However, I may have written the first, or at least one of the first, web browsers.) The difference in capitalization is exceptionally significant.

The Internet is an internet.

The Web is a web.

More background on Bob Wyman: An IT Conversations page—linked to an audio interview on some copyright-related matters—offers further bio.

When we speak of the electric grid, we are speaking of one grid among many. Yet we do not write “the Grid.” Nor do we write “the Phone Network,” or “the Television Broadcasting System.” There is simply no reason to capitalize these words. (If we were writing in German, which capitalizes all nouns, it would be different. And yes, if we were living hundreds of years ago, when English tended to capitalize most nouns, it would also be different.)